Mainland	Plain	The country
	Great Chinese
	Eastern European	RF, Ukraine, Belarus, Moldova.
	Deccan Plateau
	Dzungarian lowland
	West Siberian Lowland
	Indo-Gangetic lowland	India, Pakistan, Bangladesh
	Mesopotamian lowland	Iraq, Iran, Syria, Kuwait.
	Caspian lowland	RF, Kazakhstan
	Central Siberian Plateau
	Tarim (Kashgar)
	Turan lowland	Uzbekistan, Kyrgyzstan, Tajikistan, Turkmenistan, Kazakhstan
	East African Plateau	Kenya, Uganda, Rwanda, Burundi, Tanzania, Zambia, Malawi, Somalia, Djibouti, Eritrea, Ethiopia.
South America	Guiana Plateau	Venezuela, Brazil, Guyana, Suriname, Guyana
	brazilian plateau	Brazil
	Amazonian lowland	Brazil, Colombia, Ecuador, Peru
North America	Mississippi lowland
	Atlantic lowlands
	Mexican lowland
	great plains	USA, Canada
	Central Plains	USA, Canada

Bottom relief oceans

The following parts are distinguished in the bottom topography:

Shelf(mainland shoal) - the underwater margin of the mainland, adjacent to the coast of the land. Shelf width up to 1500 km, depth from 50 - 100 to 200 m (2000 m South Kuril basin of the Sea of ​​Okhotsk), is 8% of the world's oceans. The shelf is the most productive part of the world's oceans, where there are fishing areas (90% of seafood) and the largest mineral deposits.

continental slope lies below the shelf boundary at a depth of up to 2000 m (sometimes up to 3600 m), makes up 12% of the area of ​​the world's oceans. This part of the bottom is characterized by seismicity.

Bed The world ocean is located at a depth of 2500 to 6000 m, it occupies up to 80% of the area of ​​the world ocean. The productivity of this part of the ocean is low. The bed has a complex relief. Examples of these forms are:

a) mid-ocean ridges (Mid-Atlantic ridge, Central Indian with Arabian-Indian, Gakkel ridge), which arose as a result of the movement of lithospheric plates. The tops of the mid-ocean ridges that come to the surface form islands (Iceland, St. Helena, Easter Islands);

b) deep-water trenches - narrow depressions with steep slopes (Table 6).

The bottom of the oceans is covered with marine sediments, which cover 75% of the ocean floor and their thickness reaches up to 200 m.

Table 6

Deep sea trenches

Gutter name	Depth, m	Ocean
marian
Tonga (Oceania)
Philippine
Kermaden (Oceania)
Izu-Ogasawara
Kuril-Kamchatsky
Puerto Rico		Atlantic
Japanese
Yuzhno-Sandvichev		Atlantic
Chilean
Aleutian
Sunda		Indian
Central American

Processes affecting the formation of the earth's crust.

The processes that contribute to the formation of relief are divided into:

external (exogenous) expressed in the action of the force of attraction of the Moon and the Sun, the activity of flowing waters (fluvial processes), wind (eolian processes), the activity of a glacier (glacial processes). External processes may appear as follows:

mudflow - a stream of water, mud, stones merged into a viscous single mass;

landslides - displaced masses of loose rocks, sliding under the action of gravity;

landslides - the collapse of large boulders and slopes mountain systems;

avalanches - masses of snow falling from mountain slopes;

weathering is the process of destruction and chemical change of rocks.

External processes form small landforms (for example, ravines).

Such landforms as shields, "ram's foreheads" (low rocks in the Polar Urals), moraine hills, sandy plains - sanders, troughs, were formed during the movement of the glacier. About a million years ago, a noticeable cooling of the climate occurred on the globe. The last ice age of the Earth in 1832 was named by the English naturalist C. Lyol Pleistocene. This glaciation covered North America and Eurasia (Scandinavian Mountains, Polar Urals, Canadian Arctic Archipelago).

internal (endogenous) raise individual sections of the earth's crust and form large landforms (mountains).

The main sources of these processes are internal heat in the bowels of the Earth, which causes the movement of magma, volcanic activity, earthquakes.

Tests for self-control:

Exogenous processes include:

Weathering

Volcanism

Earthquake

Glacier activity

2. Determine the mountain range within which the peak with the highest absolute height is located:

Pyrenees 2. Andes 3. Cordillera 4. Alps

3. In one era of folding formed:

Cordillera and Pyrenees 2. Atlas and Sikhote-Alin

3. Andes and Scandinavian mountains 4. Altai and the Great Dividing Range

4. Plains with absolute heights of more than 500 m are called:

plateaus 2) lowlands 3) hills 4) depressions.

5. Philippine chute is an element:

geosynclinal zone

mid-ocean ridge

the central part of the ocean basin

1. young platform

6. Are the following statements correct (yes, no):

in the central parts of the oceanic basins, sedimentation is slower than near the continents

Volcanic eruptions can occur both on land and at the bottom of the oceans

The Antarctic Peninsula formed in the Ordovician.

7. The longest mountains ___________________________________

8. The highest peak of Antarctica ____________________________

9. highest heights and the degree of dissection of the relief is characteristic:

Central Siberian Plateau

The East European Plain

Western Siberian Plain

Amazonian lowland

10. Find a logical connection between the listed pairs and insert the missing:

Central Russian Upland - Precambrian;

Ural - Paleozoic;

Verkhoyansk Ridge - Mesozoic;

The median ridge of Kamchatka is Cenozoic;

Siberian Uvaly - _________________.

11. Moraine hills and ridges were formed as a result of geological activity ...

1. flowing waters

12. On all continents, with the exception of Antarctica, there are landforms created by geological activity ...

permafrost and flowing waters

flowing waters and wind

wind and glaciers

glaciers and permafrost

13. South America east of the Andes is dominated by

high and mid-altitude mountains

lowlands and plateaus

lowlands and highlands

low and mid-altitude mountains

14. According to the general features of their relief, they are most similar ...

Africa and South America

South America and North America

North America and Australia

Australia and Eurasia

Plains are one of the main landforms of our planet. They occupy two or three surfaces of the planet Earth and are found even at the bottom of the oceans. To determine which plain is the largest in the world, an overview of the longest of them, stretching across four continents, will help.

Plain giant of Eurasia

The East European Plain tops the ranking of the longest on the Eurasian continent. Extends on the East European platform, covering the area, starting from the coast Baltic Sea and reaching the foot of the Ural Mountains. Another name - "Russian" - the area received due to the fact that most of it is located within Russia.

On four sides, the area is bounded by five seas: from the south - the Azov and Black, and from the north - the White, Caspian and Barents. total area territory reaches 4 million km².

Throughout its length, a mostly flat-flat relief prevails, in which they successfully coexist and harmoniously alternate:

• elevations - individual points reach a height of 300 meters above sea level;
• lowlands - act as a basin of "water arteries".

Such structural features and height differences arose as a result of faults. They are characterized by tectonic origin.

The territory is conditionally divided into three lanes:

1. Northern - includes the Valdai and Smolensk-Moscow Uplands, as well as the northern Uvaly.
2. Central - represented by alternating Bugulma-Belebeevskaya, Volga and Central Russian uplands, separated by the Low Trans-Volga and Oka-Don lowlands.
3. Southern - includes the Stavropol Upland and Ergeni, separated by the Caspian and Black Sea lowlands.

The key influence on the appearance of the northern part of the Russian Plain was played by large-scale icing that occurred in the last glacial period. During this period, dozens of lakes arose in the area, for example, Beloe, Pskovskoye, Chudskoye.

The large cities of Russia are concentrated within the flat terrain and most of the country's population lives. The plain is famous for being a storehouse of minerals. most requested and large deposit– Kursk magnetic anomaly.

Long plateau in Africa

The East African Plateau is located in the southeast of the mainland. It is the most mobile and tectonically active part of the continent. Due to this, the terrain is highly dissected: the deepest depressions of the great rift system are adjacent to mountain peaks. The total length of tectonic disturbances is 6000 km.

The main features of the relief terrain of this continent include:

• the greatest rift system;
• the largest lake Victoria;
• volcanoes Meru and Kilimanjaro.

The most typical and widespread landform of the mainland are calderas. They are basins of volcanic origin. The largest caldera in diameter, referred to as Ngorongoro, is considered the giant of the planet. The volcanic activity of the continent remains intense until today. And many volcanoes are now activated.

On the plateau there are sources and watersheds flowing into Indian Ocean the largest rivers of the continent: Congo, Nile and Zambezi. Large masses the waters of the tributaries of rivers and lakes affect the climate and vegetation of the extended plateau. The vegetation cover is dominated by savannahs, at the foot of the mountain ranges there are rainforests, at an altitude of 1200 meters and above - a park landscape.

The animal world is no less diverse. On the plateau you can meet both herbivores and predators, including the "king of beasts". Drier places abound with poisonous snakes and lizards.

The Great Plains are a foothill plateau with an area of ​​1.2 million km². They include 10 US states and 3 Canadian provinces.

The characteristic landscape of the area is separate sections divided into vast plateaus by table-like ledges, the height of which reaches 300 meters:

• Missouri;
• Llano Estacado;
• Edward.

The deep-flowing Missouri and Mississippi rivers flow through the plains. Over the centuries of their existence, they managed to cut through the area with canyons, forming an extensive network of ravines. A feature of the landscape are numerous hilly areas, alternating with deep ravines and depressions - badlands. Due to the abundance of precipitation and regular weathering, their relief is extremely unstable.

Tornadoes are the main scourge of the Great Plains. The American part of the plain even falls into the “tornado alley” zone, where tornadoes are most often recorded. In the prairie region of the Great Plains winter period the shi-nuk wind prevails. This natural phenomenon is interesting in that it is accompanied by a sudden jump in air temperature, which is accompanied by snow melting. For this reason, the Indians living on the prairies deified the shi-nuk.

One of the most numerous inhabitants of the Great Plains are fold-lip bats. Their number in some caves is in the millions.

Permanent leader of South America

The Amazonian lowland is rightfully considered the largest plain on the globe. Its length is 5 million km². Formed as a result of a spill deep river Amazons under the influence of the accumulation of loose rocks.

The lowland lies in the Amazon Basin, which extends into the territory of Venezuela, Ecuador, Brazil, Guinea and Colombia. The Amazon River, originating in the Andes and carrying its waters to the Atlantic Ocean, is the silver leader in length and fullness in the world. Its waters make up about 20% of total number water flowing from all rivers into the oceans.

It occupies lowland almost 40% of the continent. She is covered in tropical wet forests referred to as the Amazon. It is conditionally divided into two parts: western and eastern.

It is a flat wide plain with a length of 1600 km. Located on its lands, the largest tributary of the Maider under the influence of tidal waves of the water giant - Atlantic Ocean during periods of flooding, it almost completely floods the surface, forming one large water surface.

For this reason, the vegetation of the western Amazon is sparse and is represented mainly by palm trees and cocoa trees. Of the animals, the most common are those adapted to life on trees: sloths, monkeys, small anteaters.

The territory, located to the east of the mouths of Tapajos and Rio Negro, is divided into a series of hills reaching a height of 350 m. The rivers here are deeper incised and do not flood the valleys during periods of high water. In this part of the Amazon summer period arid subequatorial climate prevails. The vegetation is rich and is represented by both evergreen and deciduous trees. The animal world is represented by species found in open spaces: armadillos, mazama deer, rodents.

Despite the length dense forests make the Amazonian lowland a sparsely populated part of the continent. Only a few small settlements can be found on the territory of the plain. Indigenous people live in cities along the main river continent.

Large areas of the Amazonian forests are now being cleared by the locals and used for ranching and growing soybeans. Massive logging is gradually turning huge concentrations of the Amazonian rainforest into arid savannah, upsetting the fragile ecological balance not only of the continent, but of the entire planet.

Published with minor edits

The flat terrain is often due to undisturbed rock stratification, when the layers lie horizontally or slightly inclined, but always parallel to each other. This category of plains primarily includes the original, or primary, plains, i.e., areas of the earth's crust that were previously the bottom of the sea and were the site of the deposition of marine sediments, and then were raised as a result of epeirogenic processes without disturbing the structure and turned into land . They can also be called sea plateaus, representing one of the genetic types of canteen countries.
The most extensive plains of the globe are among the sea plateaus. These include, for example, most of the Sahara, significant expanses of northern Europe and Asia, etc. The Sahara, with the exception of the eroded ancient Paleozoic folds that are exposed in its western half, stretching in the meridional direction, is a marine plateau of Paleozoic and Cretaceous age; in some places along its margins there are also tertiary deposits. The Sahara Plateau is broken up by numerous faults, so that its individual sections lie at very different heights, without losing, however, due to the dry climate and relatively weak erosional dissection, their character of a dining country.
In North America, an area with the character of a sea plateau occupies the entire central part of the mainland between the Appalachians and the Rocky Mountains. In the eastern part, from the slopes of the Appalachians westward to the Mississippi, the Paleozoic plateau extends. This plateau gradually and imperceptibly drops towards the Mississippi. The height difference is only 300-400 m. To the west of the Mississippi lies a younger prairie plateau, composed of chalk layers, gently dipping to the east. From the Mississippi, the plateau gradually rises to the Rocky Mountains, reaching considerable heights at their soles; here there are points with elevations of 1600-1800 m.
Dining countries in most cases represent the so-called plates, or platforms. Under the plates, geologists mean areas of the earth's crust, which, even in the early periods of the history of the earth, underwent plicative dislocation (were collected in folds) and at the same time were metamorphosed and penetrated by outcrops of igneous rocks. In this regard, they lost their plasticity, and passed into a state of rigid, inflexible lumps. Later mountain-building processes no longer crushed them into new folds, but only caused the formation of faults in them, as a result of which horsts and grabens could arise. Vertical movements of an epeirogenic nature could cause flooding of individual parts of the plate by the sea, which deposited horizontal layers of marine sediments lying unconformably on the ancient folded basement. After the secondary uplift and transformation into land, the sedimentary cover of such sections of the plate remained completely unmetamorphosed and retained its original, horizontal or very close to such occurrence. The thickness of horizontally lying layers can be very different in separate parts of the same slab, depending on whether we have here a subsided or relatively uplifted section of an ancient folded foundation.
The European part of the USSR lies almost entirely within the East European, or Russian, plate and for most of its length is a sea plateau, only at different times emerging from under the sea level and therefore composed of sedimentary rocks of different ages from the surface. The Precambrian folded basement, formed mainly by crystalline schists and gneisses, comes directly to the surface in several parts of the plate: 1) in the northwest - in the area of ​​the Baltic crystal shield(Soviet Karelia, Kola Peninsula, Finland); 2) in the south - in the form of the Azov-Podolsky (Ukrainian) crystalline massif and 3) in Voronezh region- in Pavlovsk and Voguchar districts.
In the Azov-Podolsky massif and in the Voronezh region, the ancient basement is exposed only in places due to the later erosion of the horizontal sedimentary cover. In some areas of the East European Plate, the Precambrian basement does not directly come to the surface, but some data suggest its shallow occurrence under the thickness of horizontal layers. Such underground horsts include the Ufa plateau of the Cis-Urals, the Ustyurt plateau between the Caspian and the Aral Sea, and the Stavropol plateau of the North Caucasus. It is characteristic that in areas of shallow occurrence of the Precambrian basement, surface sedimentary layers retain mainly horizontal occurrences. On the contrary, in places of deep occurrence of the Precambrian basement (in the depressions of the latter), the thick strata of the non-metamorphosed sedimentary layers covering it in places underwent some dislocation in the form of extremely wide and flat anticlinal folds (swells) and the same synclinal troughs (ditches). The influence of ancient dislocations in the Precambrian basement and weak younger dislocations in its sedimentary cover determines the differentiation of the East European Plain into elevated and depressed areas. The former include the Volga and Central Russian uplands, the Podolsk plateau, and others; to the second - the Oksko-Tsninskoe depression, the Caspian lowland (lies below sea level), etc. However, the fluctuations in altitude are small and do not violate the general flat character of the terrain. True, there is still no complete flatness here: in the north, the Pleistocene glaciation introduced a disturbance, creating a moraine landscape, in the south - erosion by flowing waters. At the same time, in more elevated areas, where rivers had the opportunity to cut into the surface deeper, an erosive hilly relief was created.
Another vast sea plateau within the USSR, moreover, of a relatively young age, is the West Siberian Lowland. It became dry land only from the Oligocene time. Due to its lower absolute height compared to European part Union and because of this less deep erosional dismemberment, the West Siberian lowland is even closer to the ideal plain. It has a very gentle slope to the north, in the south it is separated by a strip of the Aral-Irtysh watershed (300-500 m of absolute height) from another vast depression - the Aral-Caspian basin. The eastern part of the Aral-Irtysh watershed is a peneplanated region of Hercynian folding, composed of more or less metamorphosed Paleozoic and crystalline rocks. These folds, filling the space between the Urals and the Tien Shan, form, perhaps, the foundation of the West Siberian lowland. The latter was covered by the sea in the Upper Cretaceous, Eocene and Oligocene epochs, as well as the Aral-Caspian depression and West Side Aral-Irtysh watershed (Turgai Strait, connecting the West Siberian Sea with the Aral-Caspian basin). In the Miocene, the West Siberian Sea turned into freshwater lakes, which gradually dried up. The post-Tertiary (boreal) marine transgression did not extend far from the north - only to the Arctic Circle.
Due to the slight difference in altitude between south and north (from 160 to 200 m), the main rivers flow slowly, according to the main slope to the north; as for the tributaries, their direction is very diverse, since with the horizontal occurrence of the surface formations of the plain, the structure could not exert a directing influence on the initiation of watercourses - the watercourses follow the fall of the slopes created as a result of erosion of previously formed rivers (and sequential hydrographic network). Due to a slight fall, the erosion does not reach large sizes, and the country retains a completely flat character.
Typical sea plateaus give a number of transitions to other varieties of table countries, in which the folded base is overlapped by horizontally lying various kinds of continental formations: lacustrine, river, eolian products of weathering or volcanic activity.
As an example like this transition region you can specify the Middle Danube lowland. In place of the latter was once a mountainous country, which was a continuation of the Alps and the Carpathians. It was fractured and experienced uneven subsidence along the normal faults. The sea flooded the formed basin. The sea basin originally extended far east from here to the Caspian and Aral Seas. Subsequently, this sea was divided into parts, and the Danube lowland represented a separate brackish basin (the Panpop Sea). Gradually, it turned into a series of fresh lakes, and in the end a low-lying plain arose here. Characteristically, the original bottom of this basin, which was subsequently filled with marine Tertiary, Pleistocene and modern alluvial and eolian deposits, was far from smooth. The lowering was uneven; a number of horsts still rise above the level of the Hungarian plain. Precipitation leveled the surface, and therefore their thickness is different in different places. Throughout the entire 7 km from the western edge of the basin, the thickness of the sediments varies from 0 to 700 m, and since Mount Dreichotter, composed of the Triassic on the outskirts of the basin, rises by 400 m, this gives a difference in the levels of the original Triassic base of 1100 m.
The depression formed as a result of faults and then filled with marine Pleistocene and modern river sediments is the Lombard Lowland. The Alpine and Apennine rivers bring here a mass of rubble, sand and other products of the destruction of the mountains and continue to push the lowland into the Adriatic Sea. The Chinese Lowland is part of a vast subsidence basin filled with sediments from the Yellow River. The Bengal lowland has a similar origin.
Some authors (Lukashevich) are inclined to include in the category of canteen countries also the accumulation plains formed in mountainous countries with a dry climate by filling depressions in the relief with the products of weathering of rocks. Due to the lack of drainage of such areas, these products are not carried out of the country by rivers and can be accumulated in huge masses. Such, for example, are the loess troughs of the northern part of the Chinese provinces of Chizh and Shanxi. The height difference between the edges and the middle of these troughs can be quite significant, but the slopes are so gentle that the eye does not pick up these differences. Near completely symmetrical basins, there are also those in which loess deposits are leaning against only one slope of the basin, while the other rises more steeply from its almost horizontal bottom. Many basins in areas of dry climate (for example, in Tibet, in the Tarim Basin, in the Gobi Desert) are filled with the latest lacustrine sediments. With regard to the Gobi, it was previously assumed that since the end of the Cretaceous period it was occupied by the sea, which was connected to the Aral-Caspian basin through the Dzungarian Gates, and then, when the climate became drier, it became a victim of evaporation. Recently, however, undoubted lacustrine deposits dating back to the beginning of the Tertiary period and containing terrestrial fauna have been found here. It was these lacustrine deposits that filled mainly the pre-existing depressions, and only aeolian sediments were deposited on top of them. Thanks to the filling of depressions on the one hand, and the weathering and lowering of the watershed ranges on the other, the difference between the heights and the lowlands becomes smaller and the country takes on a more flat character. It must be borne in mind that Eastern Turkestan, the Gobi desert and the interior parts of Tibet and the Pamirs do not have a drain into the sea. Rivers end in internal drainless basins, contributing to their filling. Due to the fact that lakes located at a high level serve as the basis for erosion here, the erosion activity of rivers cannot be significant. Thus, in Eastern Turkestan, the region of the upper reaches of the Tarim River has a height of 1300 m, and the base of erosion - Lake Lob-Nor - lies at an altitude of 800 m above sea level.
Further, plains can also be formed as a result of the covering of an uneven original surface with lava covers or, in general, the filling of irregularities with the products of volcanic eruptions. We find extensive lava sheets in the western United States along the Columbia and Serpentine Rivers, where they occupy about 600,000 square meters. km, as well as in the northwestern Deccan, where the area of ​​such covers is more than 400,000 sq. km, and in some places the thickness reaches 1800 m. Eastern Siberia, between the Yenisei and the Lena, trap covers also occupy vast areas. The same covers of the Armenian Highlands have already been mentioned above.
Mountainous expanses leveled by the deposition of volcanic products are called volcanic upland plateaus.

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Ministry of Education of the Russian Federation

State educational institution higher

vocational education

"Ural State Pedagogical University"

Faculty of Geography and Biology

Control work on geomorphology on the topic: "Features of relief formation within mountainous and lowland countries"

Performed:

Student 204 group

Unopened Yana

Yekaterinburg 2011

1. Introduction 3

2. Relief formation within mountainous countries 4

2.1 Classification of mountains according to structural features 6

3. Relief formation within the plain countries 8

3.1. Genetic types plains 11

4. Conclusion 14

5. References 15

Appendix 16

1. Introduction.

The main landforms of the Earth are mountains and plains. Mountains occupy about 40% of the earth's land, and plains - more than 60%.

Mountains are vast, highly elevated above the surrounding area, strongly and deeply dissected areas of the earth's crust with a folded or folded-block structure. The mountainous countries consist of individual mountain ranges and intermountain valleys and basins separating them.

Plains - vast areas earth's surface with small (up to 200 m) elevation fluctuations and slight slopes. In tectonic relationship, they correspond to more or less stable platforms that have not shown significant activity in recent times. 42% of the plains are located on ancient platforms.

The topic of relief formation is quite closely considered in universities, at geographical and geological specialties. In grade 6, this topic is considered in the lessons "Mountains" and "Plains". And so throughout school course geography in lessons related to the topic "Relief".

The purpose of my work is to identify the features of relief formation within mountainous and lowland countries.

My job is to analyze literary sources, describe the process of formation of mountains, describe the process of formation of plains, identify the genetic types of plains and describe the process of their formation.

2. Relief formation within mountainous countries.

A mountainous country is a vast area of ​​the earth's surface with sharp fluctuations in elevation, significantly raised above the surrounding plains. Usually a mountainous country is formed as a result of a single stage tectonic development and consists of several mountain systems that differ in structure and appearance. Sometimes mountainous countries stretch for several thousand kilometers and have a complex configuration.

The highest mountains on Earth are folded or regenerated mountains. Many mountains were formed as medium-high or even low. The height of the rising mountains depends on the intensity of mountain building processes. Gradually being destroyed under the influence of exogenous processes, the mountains go down, and the higher they are, the more intense the destruction. If no new uplifts occur, high mountains turn into medium-altitude ones, and medium-altitude ones into low ones, and then a denudation plain appears in place of the mountains.

Mountains are divided into 3 groups according to their height:

-low(800 m above sea level): Northern Ural, spurs of the Tien Shan, separate ranges of Transcaucasia;

- medium-altitude(up to 2000 m above sea level). They are characterized by smoothed, soft outlines of peaks, gentle slopes (mountains of the Middle Urals). They are covered with forests and do not rise above the snow line. Very rarely, these mountains have pointed peaks, a narrow jagged ridge (Polar Urals, Khibiny, mountains of the island New Earth);

-high(more than 2000 m above sea level). Such mountains have steep slopes, their ridges are narrow, jagged. These are the mountains of Pamir, Tien Shan, Caucasus, Himalayas, Cordillera, Andes.

Mountains originate in orogenic-geosynclinal highly mobile zones of the earth's crust, otherwise in geosynclinal (folded) belts that stretch inside the continents and along their margins. In the first case, they are located between the ancient continental platforms, in the second case, between the platforms and the ocean floor. At the early stages of the development of these zones (geosynclinal stage), there is a subsidence and accumulation of thick strata of sedimentary, sedimentary-volcanogenic and igneous rocks.

Folded deformations also develop. Next comes a turning point in the development of the geosyncline, which is expressed in the transition to a general uplift of the zone, which enters the orogenic stage, i.e. mountain building stage. This stage coincides with the most intensive processes of folding and thrust formation, metamorphization of rocks, and ore formation. Geosynclinal troughs turn into folded (fold-block, fold-cover) mountain structures. Intermountain troughs are formed, and on the border with the platform - edge troughs. The troughs are filled with destruction products of growing mountains.

The process of mountain formation as a result of the development of geosynclines and the formation of folded structures occurred in different geological periods. The most ancient orogenic processes took place as early as the Archean time, covering vast expanses of modern continents. On the mainland of Eurasia, the regions of Archean folding occupy the spaces between the Yenisei and the Lena and most of the northern part of Europe.

But the current mountains, formed according to the scheme that is given, include only relatively young, Cenozoic, mountain uplifts. The older ones were leveled long ago by denudation processes and then raised again in the form of vaults and blocks by the latest tectonic movements. Arch and block, and most often arch-block uplifts led to the formation of revived mountains. They are as widespread as the mountains formed by the young, Cenozoic, folding.

2.1 Classification of mountains according to the features of the structure.

Fold mountains. These are primary uplifts during the bending of the earth layers by tectonic movements mainly in geosynclinal areas, in ocean depths. In general, on land, folded mountains are a rare phenomenon, since when rising above sea level, the folds of rocks lose their plasticity and begin to break, give cracks with displacements and disruption of the ideal folding of the successive and continuous alternation of synclines and anticlines. Typical folded mountains have been preserved only in separate areas in the Himalayas, Copenhagen, Dagestan, that is, in the mountains that arose in Alpine folding.

arched mountains. In many areas, land areas that have experienced tectonic uplift, under the influence of erosion processes, have acquired a mountainous appearance. Where uplift occurred over a relatively small area and had an arched character, arched mountains formed, a striking example of which are the Black Hills in South Dakota, having a diameter of approx. 160 km. This area experienced arch uplift, and much of the sediment cover was removed by subsequent erosion and denudation. As a result, the central core, composed of igneous and metamorphic rocks, was exposed. It is framed by ridges composed of more resistant sedimentary rocks, while the valleys between the ridges have been worked out in less resistant rocks.

Remaining mountains (plateau). Due to the action of erosion-denudation processes, mountain landscapes are formed on the site of any elevated territory. With the destruction of high plateaus, such as Colorado (in the southwestern United States), a highly dissected mountainous relief. The Colorado Plateau, hundreds of kilometers wide, was uplifted to a height of approx. 3000 m. Erosion-denudation processes have not yet managed to completely transform it into a mountain landscape, however, within some large canyons, for example grand canyon R. Colorado, mountains a few hundred meters high arose. These are erosional remnants that have not yet been denuded. As further development erosion processes, the plateau will acquire an increasingly pronounced mountainous appearance.

Blocky mountains (folded-blocky). This is the uplift of the earth's crust as a result of tectonic faults during repeated rises (movements) of ancient, destroyed mountain systems (reborn mountains). Blocky mountains often consist of layers of rocks crumpled into folds, have flat surfaces of peaks and steep rocky slopes of valleys.

volcanic mountains. There are different types. Volcanic cones, common in almost all regions of the globe, are formed by accumulations of lava and rock fragments erupted through long cylindrical vents by forces acting deep in the bowels of the Earth. Illustrative examples of volcanic cones are Mount Mayon in the Philippines, Mount Fuji in Japan. Ash cones have a similar structure, but are not as high and are composed mainly of volcanic slag - a porous volcanic rock that looks like ash. Such cones are found near Lassen Peak in California and northeastern New Mexico. Shield volcanoes are formed by repeated outpourings of lava. They are usually not as tall and not as symmetrical as volcanic cones. There are many shield volcanoes in the Hawaiian and Aleutian Islands. In some areas, the centers of volcanic eruptions were so close together that the igneous rocks formed entire ridges that connected the originally isolated volcanoes. This type includes the Absaroka Range in the eastern part yellowstone park in Wyoming. Chains of volcanoes meet in long narrow zones.

3. Relief formation within the plain countries.

A flat country is a vast territory on the earth's surface, the geomorphological appearance of which is determined by the predominance of plains. It belongs to the largest landforms - geotectures.

The relief of the plains is not very diverse. This is due to the homogeneity of the geological structure of the platform areas. continental crust and their low mobility. The significant uplift of some platform plains (for example, in Eastern Siberia and North America), which determines the great depth of their erosional dissection, is the result of neotectonic movements. The surface of the plains, in general, can be horizontal, inclined, convex, concave. The general character of its relief is varied: flat, hilly, wavy, stepped, etc.

The following plains are distinguished by absolute height:

- lowlands- their absolute height is from 0 to 200 m (Amazonian);

- hills- from 200 to 500 m above the ocean level (Central Russian);

- plateaus- over 500 m above the ocean level (Middle Siberian Plateau);

- depression- plains lying below the ocean level (Caspian).

The main geomorphological processes on the plains include fluvial, glacial, and eolian processes.

Surface flowing water is one of the most important factors in the transformation of the Earth's relief. The totality of geomorphological processes carried out by flowing waters is called fluvial. Watercourses perform destructive work - erosion, material transfer and accumulation and create developed (erosive) and accumulative landforms. Both are closely related to each other, since what was carried away by water in one place is deposited somewhere else. Erosion work is a complex process and it consists of a number of private processes:

From the entrainment of clastic rock material entering the channel from the weathered steep slopes of the valley;

From grinding or scraping (corrosion) of the bottom of the channel by solid material drawn along it (sand, pebbles, boulders);

From the dissolution of some rocks (limestones, dolomites, gypsum) with water, exposed in the channel.

A common feature of the erosive work of watercourses is its selective, selective nature. During the development of the channel, the water, as it were, reveals the most pliable areas for cutting, adapting to the outcrops of more easily eroded rocks. Where kinetic energy ("living force") flowing water falls sharply due to a decrease in slope or water flow, an excess of transported solid material is deposited in the channel of the watercourse or on a flat horizontal surface onto which the river exits the mountains: sedimentation or accumulation occurs. Apart from river valleys under the influence of erosion, ravines and gullies are formed (erosion forms created by intermittent watercourses and often forming complex-branched systems).

As examples of plains, on which one of the main geomorphological processes are fluvial, one can cite such as the Russian Plain, the Mississippi Lowland.

Glacial relief-forming processes are due to the activity of ice. A prerequisite for the development of such processes is glaciation, i.e. long-term existence of masses of ice within a given area of ​​the earth's surface. During geological history Earth has repeatedly encountered conditions under which the largest covers were formed continental ice spread over many millions of square kilometers.

The glacier performs denudation, transport and accumulation works. The destruction of rocks is called exaration. The plains are dominated by glacial accumulation. The material carried by the glacier accumulates where the flow of ice through melting and evaporation predominates. This material is accumulated at the edge of the glacier in the form of a ridge, repeating in terms of the outline of the edge. The ridge is usually curved in the form of a horseshoe and is called the terminal moraine. With intensive melting and retreat of the glacier, several terminal moraines are formed. As a result of the melting of the glacier, the bottom moraine is exposed from under the ice; There is a thick cover of detrital deposits, called the main moraine.

The glacial relief is characteristic of the North German and Polish plains, the Russian plain.

Eolian processes are associated with the effect of wind on the relief. The wind captures, separates from the surface and carries unbound soil particles. This process is called deflation. A somewhat smaller denudation role is played by the knocking out of weakly bonded particles and the destruction of rocks due to dynamic shocks of the air flow together with solid particles moving in this flow - eolian corrosion.

3.1. Genetic types of plains.

Primary plains, or marine accumulation plains- the most extensive in area. They are formed as a result of marine accumulation during temporary flooding of platform areas by transgressions of shallow epicontinental seas with their subsequent transformation into land during oscillatory positive motion. They represent the seabed exposed from under the water, covered with sedimentary marine deposits, usually already covered with a layer of eluvium or some other continental formations (glacial, fluvial, eolian), often defining the secondary micro- and mesorelief of these plains. Plains of the European part can serve as examples of marine accumulation plains. former USSR, West Siberian Plain, Caspian lowland.

Alluvial plains are formed as a result of the accumulative activity of rivers and are composed of layered river sediments from the surface. The thickness of the latter in some cases can reach a very significant thickness - several tens and even hundreds of meters (lower reaches of the Ganga river, the Po river valley, the Hungarian lowland), in others - it forms only a thin floor over eroded bedrock. The first takes place in river deltas and in areas of tectonic subsidence that captures parts of river basins, the second - in normal floodplains of mature river valleys. The alluvial plains include the Kura-Araks, Upper Rhine and other plains.

fluvioglacial plains. The transfer, sorting and redeposition of solid clastic material over large areas can also be carried out melt water glaciers flowing from under their ends or edges. These waters usually do not have the nature of regular permanent streams near their exit, often changing their water content and direction of flow from the place of exit from under the ice. They are overloaded with rewashed clastic material of moraines, sorting by size, transporting and depositing it, widely distributing it during their wandering in front of the glacier front. Examples include the Munich and other plains at the northern foot of the Alps, the Kuban, Kabardin, Chechen plains at the northern foot of the Greater Caucasus.

lake plains represent the flat bottoms of former lakes, dried up either as a result of the descent by the rivers flowing from them, or as a result of the disappearance of the dam, or due to the filling of their baths with sediment. Along their margins, such lacustrine plains are often outlined by ancient coastlines, expressed in the form of low abrasion ledges, coastal ridges, coastal dune ridges or lake terraces, indicating the former level of the lake. In most cases, plains of lacustrine origin are of insignificant size and are much inferior in size to the first three types. An example of one of the most extensive lacustrine plains is the plain of the Quaternary glacial Lake Agassiz in North America. The plains of Turaigyr-kobo, Jalanash and Kegen in Kazakhstan also belong to the lake plains.

Residual or marginal plains. These names mean spaces that originally had a large absolute altitude and a pronounced relief, representing, perhaps, once even a mountainous country, which acquired a flat character only as a result of a long-term impact of exogenous factors of destruction and demolition - pppa.ru. These plains are therefore in the final stage of downward development. mountain country, assuming a prolonged state of relative tectonic quiescence, which, apparently, rarely occurs. As an example of a marginal plain, already somewhat modified by subsequent processes, one can cite a sloping plain stretching along the eastern foot of the Appalachian Mountains of North America, gently dipping to the east.

Volcanic upland plateaus. They arise when huge masses of predominantly basic lava pour onto the surface through cracks in the earth's crust. Spreading due to its great mobility over vast areas, the lava fills and buries under itself all the irregularities of the primary relief and forms huge lava plateaus. Examples are the Columbian basalt plateau of North America, the trap plateau of the northwestern Deccan, and some parts of the Transcaucasian Highlands.

4. Conclusion

As a result of writing the work, I got acquainted with the processes that formed the main forms that make up the Earth's relief - mountains and plains. Familiarize yourself with the literature on this topic.

This work can be used in educational activities (not only school, but also university).

In general, the study of the origin of the plains and modern forms their surface is very important economic importance, since the plains are densely populated and developed by man. They have many settlements, a dense network of communications, large woodlands and agricultural land. It is with the plains that one has to deal with when developing new territories, designing the construction of settlements, communication lines, and industrial enterprises.

5. References

1. Leontiev, O.K. General geomorphology / O.K. Leontiev, G.I. Levers. - M .: Higher. school, 1988. - 319 p.

2. Lyubushkina, S.G. General Geography: studies. allowance for students. higher textbook establishments on special "Geography" / S.G. Lyubushkina, K.V. Pashkang; ed. A.V. Chernov. – M.: Enlightenment, 2004. – 288 p.

3. Milkov F.N. General geography: textbook. for stud. geographer. specialist. universities / F.N. Milkov. - M .: Higher. school, 1990. - 335 p.

4. Rychagov, G.I. General geomorphology: textbook. 3rd ed., revised. And extra. / G.I. Levers. - M .: Publishing House of Moscow. un-ta.: Nauka, 2006. - 416 p.

5. Engineering geology [Electronic resource] : scientific reference resource / Access mode: http://www.pppa.ru/geology/about02/. Date of visit: 03/07/2011

APPENDIX

Appendix 1.

Appendix 2. Collision of platforms and bowing of the earth's crust on I stage of the era of folding

Appendix 3. The emergence of mountains. II folding stage.